Piston



Patented Nov. 26, ".1935

UNITED STATES ""ylljaozazgd Lawrsligmiow,1igiypxanass Application Augustin, 1929;seislfnos aliases` (Gange-sierra n. l

This invention relates to tWo-partpistons and has for its principal object the improvement generally of such pistons,A primarily as :use ,d'inzl-internal combustion engines. f I 1 :i 1

An important object ofthe present invention is `the provision of a member or members 'preferably inthe form of a disk, to engagethevcylinder wall between the sleeveportion :and the head portion of a two-part piston;l thewalleofthe sleeve being'rsomewhat greater `in diameterthan the wall of the head portionwhich is groovedfto carry a plurality of compression rings butvomits the usual oil ring orirings,k theirfunctionfbeing taken by the disk orother piece or pieces having a circular periphery and preferably ,being slightly over-size with relation to the sleeve,.gsor that these disks or other annular members may readily be replaced with slight cost, for thedisk itself even though made of rather expensive Imaterial such for example as phosphor. bronze is" of light weight andsince only the head of the motor and the oil pan needs to be. taken .oi,; it notbeing necessary that the pistonbe disconnected from the connecting rod onlthe crank,shaft,,a lowlabor cost forreplacement is had.y f l A further objectof the present invention'is the provision ina two-part; piston of; a-baleto keep oil from the inner f acezof Ithe head (portion and to' distribute this splashedpil ltoythewr-ist pin bearing to lubricate that,memberlwArstill further object of the presentinvention'is lto design a two-part piston sothat at considerable plurality of extremely thin shims may beadded to one or more of the pistons 4of a multl-pistonengine in such yfashion that thescompression in each cylinder can be equalized. i e

Other objects of the presentinventionziconcern the fashioning of the head and sleeve portions of a two-partkpiston in such ,manner as fto `lovver the cost of theirprodution vpartieularly pression in the various cylinders oigan linternal compression motor no matter howbarefully the block lhas been made and no matter how arelfully the pistons have been standardized.. engrally ordinarily there is a slight difeceffin birithis? bonditionremainsand -noy attempt' is made to balance:V the :cylinder lpressures primarily ybecause itE lis lso: extremely'dicult .to alter the -idistance from theactiveputer face ofthe-head to the'axis of- -thelwristpinlz/Thisllias `been'taken care of in 5' the present invention; by: prov-iding i means Wherebythe.v` pistone/having f the i greatest 1 compression is assembled withoutshims and. each of the other pistnsL-are.built'nup by? aicut :and .try `method by theaddition'ofifrom onen-to alhalfdo'zenbr more 10 shims which f may@ to*r as tlittle z as one-thousandthofanin'c'hirr thicknessand which may run toi as. much as flve.thousandths-, .although fgenerally being .betweenthefztwo filgures'stated. The balancing of f thef-cylinderpressures is'y of course 15 performed'ffrom therheadvendfof the Amotor but the ,fpi'stonsleeve is,notsdisconnected; from the connectingrodforf mathe mainc'ranklshaft duringjthaadjustingi l 11 .n Car-bbnzgfisy kformada thief compression chamber 20 by; the f seeping' of:` oil pastI the foil ring or rings and' itis depositedon the rcompression ringsto an extent-v` 'such'as toffunbalance :the pistons; vIt is seeminglyimpossiblevto construct afyielding oil ring which willrprevent absolutely the'formation 25 of;carb.on f-infftheifcombustion chamber above the top face ofggthe- :piston-A l butl 'all can .substantially eliminate thefformationlof carbonfinfsthe combustion chamber and on the compressionringsby using; inl/place sofv the "yieldings florus'pliti oil` ring 30 an'.iunyieldingfrings-whichf prefervtofhave inv the form of rafdisktwhichi ldis'kl fissupport'ed preferably by bridges;:gextendingxrdiame'trically V'across the head and the sleeverinyalignment witheach other. This fdisk-tor,A these ydislirs',` fas z-thev lcase ),mayi be, t 35 very.;V snugly indeed thea cylinderawallwand .return theloil tot.thetinsidef offth sleeve; Where itY will furnish positive zlubricationrftoi:thewrist pin. WhilefIdolnotv wish beflimited in :any way by thiSJstatement, ait'ismyv,preierence` to -make the 40 disks of yphosph'orljbrone; ftheI head "off :aluminum alloyandsthesleeverof-cast. "on-.f It'rWill be obvious to.. thoseskilledsin fthe-,art that othermetal or metal'smaybe; substituted: withoutdeparting from the spirit of my invention Y' .if Infthedrawngszfu J.ig'urefll iszaverticalcetralf e'ction frFigureGZlis ai rcentrallfvertical;zsectionltaken rat rightlanglesl toiithellcutting plane of ligurel-.ilx v4 the piston body or sleeve has two integral bosses I I bored as at I2 to receive the wrist pin I4 which pivots the piston to the connecting rod I5. The top of the sleeve is open save for the provision of a transverse bridge I1 which I prefer to have integral with the body or sleeve as by having these two elements in one piece or casting I can turn the piece on a lathe without the necessity for the usual blocking and I therefore form and iinish the outer cylindrical wall of the sleeve at a minimum labor cost. j y

The head portion 20 has a circular top face 2I and annular wall 22 which is cut by a plurality of grooves 23 which receive ordinary compression rings omitted in the figures as they are to be of standard type and have no part in the present invention serving only their usual function to prevent leakage of pressure from the combustion chamber. n

Between the head and sleeve portions of the piston I provide one or more oil scraping disks 25 and 26. These disks are given different numerals in the drawings since I must provide some means such as the orinces 21 to returny the oil scraped by the disk 25. The upper disk need have no such oil return. hole since no voil will ever pass it. Inproviding two or more disks the diameter of the -upper diskshould be larger by an extremely small amount. In having a plurality of disks it is my preference to replace the lowest disk and to insert the new disk at the top, Inwhich case the top disc will always be larger in diameter and the lowest disk smallest in `diameter due to the wear. In such cases naturally all the disksk will have the oil holes although the holes will have no function for the time being in the top disk.

The bridge 30 is substantially identical with the bridge II matching it in shape and like it having its two parallel faces oiset with respect to the face of the horizontal edge of the main portion of the head or sleeve. The circular or arcuate face 3| of. each bridge is less in diameter than the diameter of the sleeve I0 to provide space for the return of oil to the inside of the sleeve. While I prefer that the bridges shall extend from side to side of the head and sleeve these pieces may, by omitting their function of saving labor cost, consist of simple inturned lugs but only by a sacrifice of efciency.

From the bridge I1 of the sleeve extends a center pin 33 which ts ratherl snugly through ,the central hole 34 of the disk and also rather snugly into a hole or cavity 35 in the bridge 30 of the piston head 2Il. For convenience in manufacturing, the studs 38 are made with right and left hand threads fitting permanentlyinto tapped openings in the bridge lII and extending somewhat loosely through openings 40 in the :sleeve bridge Il and through openings 4I in the disk.

The shims 45 are extremely thin and for convenience merely, are made of the same size and shape in plan as the two bridges. Each shim has a central perforation 46 to fit onlthe center guide post 33 and two somewhat larger holes 41 to receive the two studs 38.' Y

In assembling the device the pistons are placed in their respective cylinders omitting all shims. The piston in the chamber having the, greatest compression remains shimless but each of the other pistons are supplied with one or more of the shims so as to decrease the cubic capacity of the compression chamber and so as to equalize the pressure in the four, six, eight or more cylinders. When the correct number of shims or rather when shims of the correct thickness have been added to equalize the compression pressures the castle nuts 48 are tightened inplace on the studs 40 and are locked in place by the cotter pins 49 which pass through holes 50 in the studs. 5

I claim as my invention: y

1. A piston having a sleeve portion and a compression ring portion and having a groove between said sleeve portion and said compression ring portion, and an oil scraping disc between 10 said portions and having its margin located in said groove, said margin having an unbroken peripheral surface.

`2. The device of claim 1 in which the disk is of i phosphor bronze supported on both sides l5 throughout more than half of its area and having its entire periphery unsupported.

. 3. A two piece piston comprisinga head portion and a sleeve or body portion, a disk between the head portion and the sleeve or body portion, 20 and shims kbetween the disk and each portion saidshims being of less diameter than the head and sleeve portions and said disk being of greater diameter than said portions whereby the unsupported margin of i the. disk permits flexing dur- 25 ing operation of the piston. i

4.*A piston sleeve having twoopen ends, two wrist pin bosses diametrically disposed, and a single strengthening. baracross one open end centrally, said bar being iiat and integral with 30 the sleeve and having its median line at right angles to the axis of saidv bosses, the length of the bar beingless than the outside diameter of the sleeveA and projecting above the plane of the strengthened end. 35

5. A piston sleevehaving two open ends, two wrist pin bosses diametrically disposed, a bridge across one open end centrally, said bridge having its median line at right angles to the wrist pin axis, and a central positioning stud carried 40 by said bridge, said bridge being perforated between the stud and each side to receive fastening means to secure it to a head portion.

6. A piston having'a sleeve of one diameter, a grooved head of smaller diameter, and having 45 between the head andthe sleeve a `replaceable disk of greater diameter than said sleeve, said disk having its peripheral margin spaced from the headand sleeve whereby to provide a iiexible oil scraping member. 50

'7. A piston'` for an internal combustion engine having a sleeve or body portion and a cup-like f a transverse diametric bridging member on each 65 portion, means on the bridging'members for securing the sleeve and headportions together, an oil scraping disk between said portions and shims for spacing said disk from said portions, said shims being of less area than the disk whereby 70 a substantial peripheral margin on each side of thefdisk is free.

9. A piston for internaly combustion engines comprising a sleeve portion and a head portion, a transverse diametric bridging member on each 75 portion having about one-half the area of a circular cross section of the piston, shims of approximately the same size as the bridge members for spacing the sleeve 'portion from the headl portion and oil scraping disks interspersed with said shims so. as to be spaced from each other and from said bridging members.

10. In a two-piece piston, consisting of a sleeve and a cup-like head, means for connecting the head and sleeve comprising a. flat cross bar integrally connecting the walls and diametrically disposed across the open end of the head, said bar having a. length less than the diameter of the head and projecting laterally beyond the plane of the open end, a similar cross bar integrally connecting the walls and diametrically disposed across one end of the sleeve, said sleeve cross bar having a length less than the diameter of the sleeve and projecting laterally beyond the plane ot said one end, whereby when said head and sleeve are connected together by said cross bars a space is left between their adjacent ends.

11. The piston of claim 10 in which an oil scraping disk is disposed between the head and 10 sleeve and has a diameter greater than that of either.

LEWIS J. TE'I'LOW. 

